The spectra of stars are described in terms of spectral classes. In order of decreasing temperature, these spectral classes are
O, B, A, F, G, K, M, L, T, and Y
. These are further divided into subclasses numbered from 0 to 9.
What are the 7 letters of star classes?
The stars are divided into 7 classes designated by the letters
O, B, A, F, G, K, and M
; the hottest stars (O and B) are blue-white in color, while the coolest (M) are red. Each of the letter classes has subdivisions indicated by numerals 0 through 9.
What are the 7 parts of star?
All main sequence stars have a
core, radiative and convective zones, photosphere, chromosphere and corona
.
What are the different spectral classes of stars?
| Spectral Class Effective Temperature (K) Other Features | A 7,500 – 10,000 strong H lines, ionised metal lines | F 6,000 – 7,500 weak ionised Ca + | G 4,900 – 6,000 ionised Ca + , metal lines | K 3,500 – 4,900 Ca + , Fe, strong molecules, CH, CN |
|---|
What are the 7 spectral types?
- O (Blue) (10 Lacerta)
- B (Blue) (Rigel)
- A (Blue) (Sirius)
- F (Blue/White) (Procyon)
- G (White/Yellow) (Sun)
- K (Orange/Red) (Arcturus)
- M (Red) (Betelgeuse)
What is the most common spectral class?
| Star Type | O | Color | Blue | Approximate Surface Temperature | over 25,000 K | Average Mass (The Sun = 1) | 60 | Examples | 10 Lacertra |
|---|
What is the biggest star?
The cosmos is full of objects that defy expectations. Although it’s difficult to pin down the exact traits of any given star, based on what we know, the largest star is
UY Scuti
, which is some 1,700 times as wide as the Sun.
What color is the hottest star?
White stars are hotter than red and yellow.
Blue stars
are the hottest stars of all.
How much light a star actually gives off is called its?
Astronomers also measure
luminosity
— the amount of energy (light) that a star emits from its surface.
What do star letters mean?
The full order of classification is O, B, A, F, G, K, M – more easily remembered by using the mnemonic “Oh Be A Fine Girl/Guy, Kiss Me”. This also orders adult (main
sequence
) stars from hot to cool; the hottest (and largest) main sequence stars are O and B type, while the coolest (and smallest) stars are M dwarfs.
Why do stars twinkle?
As light from a star races through our atmosphere, it bounces and bumps through the different layers, bending the light before you see it. Since the hot and cold layers of air keep moving,
the bending of the light changes too
, which causes the star’s appearance to wobble or twinkle.
What type of star is our Sun?
Our Sun is
an ordinary star
, just one among hundreds of billions of stars in the Milky Way Galaxy. As the only star we can observe in detail, it provides a basis for our understanding of all stars. The Sun is composed almost entirely of hydrogen and helium gas.
Where are stars born?
Stars are born
within the clouds of dust and scattered throughout most galaxies
. A familiar example of such as a dust cloud is the Orion Nebula. Turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction.
What classification of stars is the coolest?
The spectral sequence is also a colour sequence: the O- and B-type stars are intrinsically the bluest and hottest; the
M-, R-, N-, and S-type stars
are the reddest and coolest.
What are the different sizes of stars?
Stars come in huge range of different sizes.
Neutron stars can be just 20 to 40 km in diameter
, whereas white dwarf can be very similar in size to Earth’s. The largest supergiants, on the other hand, can be more than 1500 times larger than our Sun.
What is star life cycle?
A star’s life cycle is
determined by its mass
. The larger its mass, the shorter its life cycle. A star’s mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust from which it was born.
